Capture stdout from node:slim docker pull so it doesn't contaminate the final

output.

Author: Peter Amstutz

cwltool/sandboxjs.py

@@ -2,10 +2,13 @@
 import json
 import threading
 import errno
+import logging
 
 class JavascriptException(Exception):
     pass
 
+_logger = logging.getLogger("cwltool")
+
 def execjs(js, jslib, timeout=None):
     nodejs = None
     trynodes = (["nodejs"], ["node"])
@@ -24,7 +27,8 @@ def execjs(js, jslib, timeout=None):
             nodeimg = "node:slim"
             dlist = subprocess.check_output(["docker", "images", nodeimg])
             if "node" not in dlist:
-                subprocess.check_call(["docker", "pull", nodeimg])
+                nodejsimg = subprocess.check_output(["docker", "pull", nodeimg])
+                _logger.info("Pulled Docker image %s %s", nodeimg, nodejsimg)
             nodejs = subprocess.Popen(["docker", "run",
                                        "--attach=STDIN", "--attach=STDOUT", "--attach=STDERR",
                                        "--sig-proxy=true", "--interactive",